[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 01/11] kexec: introduce kexec_ops struct
On Fri, Nov 23, 2012 at 10:51:55AM +0000, Jan Beulich wrote: > >>> On 23.11.12 at 11:37, Daniel Kiper <daniel.kiper@xxxxxxxxxx> wrote: > > On Fri, Nov 23, 2012 at 09:53:37AM +0000, Jan Beulich wrote: > >> >>> On 23.11.12 at 02:56, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote: > >> > On 23/11/2012 01:38, H. Peter Anvin wrote: > >> >> I still don't really get why it can't be isolated from dom0, which would > >> > make more sense to me, even for a Xen crash. > >> >> > >> > > >> > The crash region (as specified by crashkernel= on the Xen command line) > >> > is isolated from dom0. > >> > > >> > dom0 (using the kexec utility etc) has the task of locating the Xen > >> > crash notes (using the kexec hypercall interface), constructing a binary > >> > blob containing kernel, initram and gubbins, and asking Xen to put this > >> > blob in the crash region (again, using the kexec hypercall interface). > >> > > >> > I do not see how this is very much different from the native case > >> > currently (although please correct me if I am misinformed). Linux has > >> > extra work to do by populating /proc/iomem with the Xen crash regions > >> > boot (so the kexec utility can reference their physical addresses when > >> > constructing the blob), and should just act as a conduit between the > >> > kexec system call and the kexec hypercall to load the blob. > >> > >> But all of this _could_ be done completely independent of the > >> Dom0 kernel's kexec infrastructure (i.e. fully from user space, > >> invoking the necessary hypercalls through the privcmd driver). > > > > No, this is impossible. kexec/kdump image lives in dom0 kernel memory > > until execution. That is why privcmd driver itself is not a solution > > in this case. > > Even if so, there's no fundamental reason why that kernel image > can't be put into Xen controlled space instead. Yep, but we must change Xen kexec interface and/or its behavior first. If we take that option then we could also move almost all needed things from dom0 kernel to Xen. This way we could simplify Linux Kernel kexec/kdump infrastructure needed to run on Xen. Daniel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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